Daikin Error Code A2u: R-32 leak function test (Furnace)

Updated October 15, 2026 · by Aurora Star Tech Inc.

Daikin error code A2u on a furnace means: R-32 leak function test. It is also called Daikin diagnostic code A2u.

Low severityFurnaceDaikin DR96TN/DD96TN

Homeowner? What Daikin code A2u means for you

Usually minor Your furnace is reporting: R-32 leak function test. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Daikin error code A2u mean?

Menu item that simulates an R-32 refrigerant leak so the installer can check the furnace response. It only works when no alarm or fault is active. After YES is chosen the control shows the leak code EAL, shuts off gas heat, energizes the optional ventilation and alarm outputs and runs the blower at maximum airflow. The test ends after 5 minutes, if a fault appears, or if the user turns it off.

Applies to: Daikin DR96TN/DD96TN two-stage furnaces

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Daikin models that use code A2u

DD96TN0403BN DD96TN0603BN DD96TN0803BN DD96TN1005CN DR96TN0303AN DR96TN0403AN DR96TN0603AN DR96TN0603BN DR96TN0803BN DR96TN0804CN DR96TN1004CN DR96TN1005CN DR96TN1205DN

Other Daikin Furnace codes

Code	Meaning
1AC	Cooling, low stage
2AC	Cooling, high stage
Cr	Code release number
E10	Grounding fault / poor neutral connection
E11	Flame rollout switch open
EAF	R-32 sensor communication lost - mitigation mode
EAL	R-32 refrigerant leak detected - mitigation mode
EAr	A2L relay fault - mitigation mode
EAS	R-32 sensor fault - mitigation mode
EbL	Low circulator current - hard lockout
EbU	Unexpected circulator current - hard lockout
EE0	Lockout - too many ignition retries (3)

All Daikin Furnace error codes →

Daikin code A2u: homeowner questions

What does Daikin code A2u mean?

R-32 leak function test. Menu item that simulates an R-32 refrigerant leak so the installer can check the furnace response. It only works when no alarm or fault is active. After YES is chosen the control shows the leak code EAL, shuts off gas heat, energizes the…

Is it safe to keep using my furnace with code A2u?

Usually yes. Code A2u is normally minor, but if it keeps coming back have it checked.

Can I reset Daikin code A2u myself?

You can try one reset (power off for 30 seconds, then on). If Daikin code A2u comes back, the cause is still there and a licensed technician should check it.

Who can fix Daikin code A2u near me?

Aurora Star Tech Inc. repairs Daikin furnaces in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean

Troubleshooting guides

Blowing cold air All brands · Furnace
No heat All brands · Furnace
Short cycling All brands · Furnace
Control display blank, furnace dead - Daikin DR96TN/DD96TN Daikin · Furnace
Furnace not paired with R-32 cooling - disable A2L function - Daikin DR96TN/DD96TN Daikin · Furnace
No heat - Daikin DR96TN/DD96TN Daikin · Furnace
Reset the furnace control to factory defaults (rFd) Daikin · Furnace
Run the R-32 leak function test (A2u) Daikin · Furnace
Turn off R-32 monitoring when no R-32 system is fitted (A2E) Daikin · Furnace
View and clear the stored faults (L6F / F10) Daikin · Furnace

Source: Daikin DR96TN-DD96TN service RSD6612304 (05-2024), R-32 Information - A2L Verification p.10. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.